NICHD will evaluate adolescent injury causes, violence, and related behaviors through participation with the World Health Organization Study of Health Behavior in School Children (WHO-HBSC). The study addresses the hypothesis that U.S. youth may have adopted lifestyles that place them at greater risk for certain health problems than their counterparts in other nations. The WHO-HBSC is used to monitor and investigate patterns, determinants and effects of health related behaviors. International comparisons test the degree to which such behavior is a natural and inevitable part of current adolescent development. Analysis of differences and similarities will be conducted to help identify influential factors included family, school and peers. The Epidemiology and Human Learning and Behavior Branches of NICHD are collaborating to perform the U.S. survey during the 1988 school year. NICHD is applying to become a full participant for the U.S. after completing a required preliminary survey through collaboration with the Substance Abuse and Mental Health Services Administration (SAMHSA). The WHO coordinates a quadrennial survey that compares health behavior in adolescents in 28 countries. SAMHSA collected pilot data in a school based study of U.S. adolescents during 1996. The data will prove invaluable for both international and domestic comparisons of injury and related behaviors in adolescents to target interventions since injury is the leading cause of death for children in the U.S.